Insulated glass is heavily utilized in modern residential and commercial construction. In many areas of the country, building codes require the use of insulated glass windows as a mandatory energy conservation measure as window with a single pane of glass alone have very little insulating value.
Insulated glass generally includes two panes of glass separated by a space. The perimeters of the two panes of glass are sealed to one another to allow no movement of ambient air into the space between the two panes of glass. The space is filled with dehydrated air or with another gas. To avoid later failure and fogging of the interior surfaces of the panes of glass, insulated glass must be tightly and permanently sealed.
Traditionally, insulated glass windows have been constructed by assembling an insulated glass unit and later inserting it into a sash. An insulated glass (IG) unit is constructed by sealing two panes of glass to a spacer that fits between the two panes of glass all the way around the perimeters of both planes of glass. Once the insulated glass unit is assembled and sealed, it is then inserted into a sash or frame. A sash typically includes a rectangular frame constructed of wood, vinyl or metal. The sash generally has a rabbeted construction so that the insulated glass unit may be recessed into the sash. The insulated glass unit is then sealed to the sash using sealants or caulking compounds. The completed sash unit then may be used in a larger insulated window assembly.
If moisture or other undesirable materials are left in the space between the pane fogging or a dirty appearance will develop on the interior surfaces of the glass panes. It is highly desirable to avoid this outcome because only replacing the insulated glass can cure it. Therefore, desiccants are introduced into the space between the panes during the assembly process to absorb water vapor and any other gaseous or vaporous contaminants that might reduce the clarity of the insulated glass unit.
Recently, a new development in the insulated glass arts has arisen. A spacerless sash material has been developed that allows windowpanes to be sealed directly to the sash to create insulated glass sashes eliminating the requirement of a separate spacer between the two glass panes.
Most IG units are manufactured with automatic equipment that is capable of supporting two panes of glass and that have the adhesive or sealant deposited on the lateral inside surface of the glass that adjoin to the spacer frame. A desiccant material is deposited on the inside surface of the spacer frame and the two panes are pressed against the spacer frame to trap gas with the desiccant material in the gap formed by the two panes of glass. Another adhesive or sealant is usually deposited on the outside surface of the spacer frame and between the two panes of glass to further seal the IG unit together. The IG units are then used as components of the window or doorframe.
Current IG fabrication equipment is primarily focused on high volume IG unit fabrication and is not conducive to fabrication of custom designed windows or door frames having glass unit shape requirements that vary from the high volume stock. Glazing equipment that can be used on a smaller scale has the drawback of forming beads of sealant on a glass surface that is not consistent from lot to lot. The size of sealant bead is typically dependent on the operator's experience and speed. A more experienced operator can produce can produce more uniform and appropriately sized beads of sealant.
Conventionally, insulated glass sashes have been assembled by laying the sash on a flat surface, applying a sealant material to the sash or to the insulated glass unit and lowering the horizontally supported insulated glass into the sash. When using a spacerless sash material, insulated glass is applied to the spacerless sash from both sides. In the assembly of a spacerless sash, the glass pane is applied to a first side of the sash, then the sash is turned over and a second glass pane is applied to the second side of the insulated sash to complete the assembly.
There is a need in the window and door fabrication industry for glazing equipment and a process for reducing the cost and the number of process steps required to manufacture a finished door and window. Further, there is a need for glazing equipment that provides for consistent sealant bead sizes irrespective of operator speed and experience. Furthermore, the speed-limiting step in the construction of insulated sashes is often that of applying sealants and desiccants. Sealants and desiccants are applied as a vicious liquid, much in the manner that a caulking gun is used to apply caulk. It would be a great benefit to the art if the application of sealant and desiccant to insulated sashes could be done more quickly, thus allowing greater speed of throughput in the assembly process.